Air Line Protection Coupling For A Catheter

ABSTRACT

A catheter connector is described having a hydrophobic end cap or washer located around the end opening to the connector&#39;s lumen. The diameter and length of the lumen below the washer is sufficiently large enough to accommodate an absorbent tubular filter that changes color when exposed to fluid. The washer acts to limit the size of the water droplet that might adhere to the end of the catheter and help maintain surface tension on the droplet to prevent it from entering the lumen. The hydrophilic tubular filter absorbs any water that might pass by the washer and thus keeps the lumen hole open.

RELATED APPLICATIONS

This application is a continuation of and claims priority to U.S. patentapplication Ser. No. 14/643,997 filed Mar. 10, 2015 entitled Air LineProtection Coupling For A Catheter, issuing on Nov. 13, 2018 as U.S.Pat. No. 10,123,723, which claims benefit of and priority to U.S.Provisional Application Ser. No. 61/967,070 filed Mar. 10, 2014 entitledAir Line Protection System, both which are hereby incorporated herein byreference in their entireties.

BACKGROUND OF THE INVENTION

Presently, biologically compatible air-based pressure monitoringcatheters are used in a number of medical applications to monitorpressure at various locations within a mammalian body. For example,air-based pressure monitoring catheters may be inserted into the skullof a patient thereby permitting the external monitoring of intra-cranialpressure.

Currently, a number of air-based pressure monitoring catheters have beendeveloped. Generally, these air-based pressure monitoring catheterscomprise a catheter having an air lumen formed therein whichcommunicates with a bladder positioned at or near its distal end. Inaddition, the catheter includes a connector located at or near itsproximal end, which may be connected to an external pressure transducer.

During use, the volume of the bladder attached to the catheter changesas pressure varies in accordance with Boyle's Law (P₁V₁=P₂V₂). As aresult, the pressure of the gas within the catheter becomes equal tothat of the environment surrounding the bladder. The media surroundingthe bladder must be capable of movement to accommodate the variations inbladder volume as pressure changes.

The use of air-based pressure monitoring catheters in low or negativelypressurized environments has proven problematic. When the proximalconnector is open to atmospheric pressure in the process of periodicallyreplacing air lost by diffusion through the bladder, the externalpressure extant in the body site monitored on a bladder will expelresidual air from the bladder. If the pressure is low or negative, asignificant amount of residual air may remain in the bladder. The amountof air injected is intended to be sufficient to keep the bladder in anactive state for a period of 8 hours. If this volume is added to theresidual air in a bladder that has not been completely collapsed by theenvironment around it, the sum of the residual air and injected airexceed the intrinsic volume of a fully shaped bladder. Should thishappen, a positive pressure is established in the bladder. The bladderis now unable to read pressure below the internal pressure created.

Air management systems such as those seen in U.S. Pub. No. 2007/0208270and U.S. Pat. Nos. 6,447,462 and 8,360,988, which are all hereinincorporated by reference, allow a user to adjust the amount of air in asystem. For example, these systems allow a user to vent the air passageof the catheter to the open environment, then charge the passage with anamount of air. In this respect, the pressure in the resulting chargedpassage can be monitored and a pressure within the patient (e.g., withinthe patient's skull) can be determined.

To function properly, the air in these catheters with air-based pressuresensors must be free to move within the lumen without obstruction. If asmall amount of water should get in the lumen, air is constrained frommoving freely, preventing an accurate pressure reading from beingdetermined.

SUMMARY OF THE INVENTION

One embodiment of the present invention includes a catheter connectorhaving a hydrophobic end cap or washer located around the end opening tothe connector's lumen. The diameter and length of the lumen below thewasher is sufficiently large enough to accommodate an absorbent tubularfilter that changes color when exposed to fluid. The washer acts tolimit the size of the water droplet that might adhere to the end of thecatheter and help maintain surface tension on the droplet to prevent itfrom entering the lumen and also prevents the tubular filter fromabsorbing liquid, should the proximal end contact a small pool ofliquid. The hydrophilic tubular filter absorbs any water that might passby the washer and thus keeps the lumen hole open. Additionally, bychanging color, the filter can alert a user that the connector has beenpotentially compromised with liquid. Preferably, the connector iscomposed of one or more clear or transparent body components that allowa user to better see the color of the filter.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other aspects, features and advantages of which embodiments ofthe invention are capable of will be apparent and elucidated from thefollowing description of embodiments of the present invention, referencebeing made to the accompanying drawings, in which

FIG. 1 illustrates a simplified, side view of one embodiment of apressure monitoring catheter, a connector, and an air management systemaccording to the present invention.

FIG. 2 illustrates a perspective view of an air management systemaccording to the present invention.

FIG. 3 illustrates a cross sectional side view of a connector for apressure monitoring catheter.

FIG. 4 illustrates an exploded cross-sectional side view of theconnector of FIG. 3.

FIG. 5 illustrates a side view of the connector of FIG. 3.

FIG. 6 illustrates a cross sectional side view of the connector of FIG.3.

FIG. 7 illustrates an exploded view of another embodiment for a pressuremonitoring catheter.

FIG. 8 illustrates an end view of the pressure monitoring catheterconnector of FIG. 7.

FIG. 9 illustrates a cross section side view of the pressure monitoringcatheter connector in FIG. 8 along lines A.

FIG. 10 illustrates a top view of a female connector used with thepressure monitoring catheter connector of FIG. 7.

FIG. 11 illustrates an end view of the female connector of FIG. 10 usedwith the pressure monitoring catheter connector of FIG. 7.

DESCRIPTION OF EMBODIMENTS

Specific embodiments of the invention will now be described withreference to the accompanying drawings. This invention may, however, beembodied in many different forms and should not be construed as limitedto the embodiments set forth herein; rather, these embodiments areprovided so that this disclosure will be thorough and complete, and willfully convey the scope of the invention to those skilled in the art. Theterminology used in the detailed description of the embodimentsillustrated in the accompanying drawings is not intended to be limitingof the invention. In the drawings, like numbers refer to like elements.

The present invention is directed to a plug connector assembly 100 thathelps prevent liquid from entering the air lumen of an air-basedcatheter system. As seen in FIG. 1, a catheter 110 with an air bladderis connected to one end of a male connector 114 of the connectorassembly 100. The male connector 114 is sized and configured to couplewith a female connector 125 of an air management system 126. In oneembodiment, the air management system can be that shown in FIG. 2, whichis described in greater detail in U.S. Pat. No. 8,360,988, the contentsof which are hereby incorporated by reference.

As seen in FIGS. 3 and 4, a continuous passage 111 is created betweenthe lumen of the male connector 114 and the catheter 110, terminating atthe end of the male connector 114. When plugged into the femaleconnector 125, the passage 111 connects to the passage 112 of the airmanagement system 126, allowing a desired amount of air to be injectedinto the catheter 110 and allowing a pressure transducer 128 to measurechanges in the air pressure within the lumens 111 and 112. The O-ring116 on the connector 114 helps maintain the seal between the lumens 111and 112, thereby maintaining air pressure in the system.

Since the lumens 111 and 112 tend to have a relatively small diameter,even small amounts of fluid can block or interfere with the free flow ofair in the system, preventing the air management system 126 fromaccurately measuring pressure. In order to help prevent fluid into thesystem, the male connector 114 includes a cap or washer 122 locatedwithin an inset area 119 and which is preferably composed of ahydrophobic material. As seen in FIGS. 5 and 6, if a larger liquiddroplet 12 or smaller water liquid 14 should attach itself to the end ofthe male connector 114, the hydrophobic material of the washer 122 helpsmaintain the surface tension of the droplet 12, preventing the liquidfrom entering the lumen 111.

The male connector 114 further includes a fluid absorbent, hydrophilicfilter 120, having a tubular shape through which the lumen 111 passesthrough and which is located adjacent to the hydrophobic washer 122. Ifliquid does get pushed into the lumen 111, the filter 120 will absorbthe liquid, keeping the lumen 111 clear of liquid obstruction.

The filter 120 can further act as a warning system to the user,indicating that fluid has entered the lumen 111 and that the maleconnector 114 has been compromised. In one embodiment, the body of themale connector 114 is composed of a clear material and the filtercontains a material that changes color when exposed to water. Forexample, the filter 120 can contain dried, food-grade dye, such as anyFD&C rated food dye, such that when contacted by liquid, the dye causesthe filter 120 to change to a bright color. Since the male connector 114is composed of a clear material, the user can clearly see the colorchange and therefore can replace the male connector 114 on the catheter110.

Optionally, additional filter material 124 can be located at the end ofthe female connector 125, around the opening to lumen 112. Like filter120, filter 124 can absorb liquid and can further include acolor-changing substance to indicate exposure to liquid.

FIGS. 7-9 illustrate another embodiment of a male connector 200 that isgenerally similar to the previously described connector 114. Forexample, the connector 200 includes a body 202, a lumen passage 214, atubular color-changing filter 206, a hydrophobic cap/washer 208, and ano-ring 204.

As best seen in FIG. 9, the connector 200 also includes a barbed endportion 212 that allows easy connection and disconnection to a catheter110. Also, a raised key region 210 aligns with a keyway 224 on thefemale connector 220 (FIGS. 10 and 11), allowing connection of the maleconnector 200 at only a single rotational orientation. By allowing onlya single rotational orientation, a latch mechanism can be included,latching the male connector 200 with the female connector 220.

Since pushing the male connector 200 into the female connector 220 caninject a significant and possibly undesirable amount of air into thelumens of the catheter 110 and air management system 126, the femaleconnector includes two venting channels 222 that allow air to escape asthe male connector 200 is pushed in.

It should be understood that while the shapes and sizes of variouscomponents have been described, variations on these components are alsocontemplated according to the present invention. For example, while thefilter member has been described as tubular, other shapes are alsopossible, such as a plurality of elongated, axial filter strips or aconical tube. In another example, the hydrophobic cap or washer may begenerally circular, square, rectangle, or any other shape.

Although the invention has been described in terms of particularembodiments and applications, one of ordinary skill in the art, in lightof this teaching, can generate additional embodiments and modificationswithout departing from the spirit of or exceeding the scope of theclaimed invention. Accordingly, it is to be understood that the drawingsand descriptions herein are proffered by way of example to facilitatecomprehension of the invention and should not be construed to limit thescope thereof.

What is claimed is:
 1. A connector assembly for an air-based catheter,comprising: a connector body having a first end, a second end, and alumen extending between and opening at said first end and said secondend; said first end being configured to connect to a catheter and saidsecond end being configured to connect to a receptacle in communicationwith an air management system; a hydrophobic cap member located at saidsecond end of said connector body; said hydrophobic cap member having afixed aperture opening to said lumen of said connector body; and, afilter member located within said lumen near said second end opening tosaid lumen of said connector body; wherein, when said connector assemblyis connected to said receptacle in communication with said airmanagement system, a single, continuous air passage is created with saidair-based catheter and said air management system.